Hi. I have most of my pdfs as Adobe, but just recently I have not been able to open them. The only way I can open most files is by using another PDF software. In fact Word, JPG and other software I am having the same issue - I have to find another software to open the file (if it can). I am also wondering if someone has hacked into my PC - how can one find out if this has happened?
Does the same thing happen in File Explorer?
It usually just means you need to reinstall the program in question. Different PDF software often fights over the registry and trashes things other software has set up in it.
You can use most, if not all, web browsers to open and view PDF files, no additional software required. I have assigned PDF's to Open with... Firefox, works perfectly and also gives you PDF previews in the DOpus viewer if that is what you are specifically after.
It seems it does not happen in File Explorer.
Have you tried reinstalling your PDF viewer? That fixes most problems with them.
What actually goes wrong? Is there an error message?
What exactly are you trying to do? Open the files in another window by double-clicking them, or open them in Opus's preview pane within the main Opus window? Or something else?